#!/usr/bin/env python3
"""Leave modem mode when the USB host goes away, instead of after a fixed timeout.

Stock firmware dropped out of hotspot mode if the host was quiet for 20 seconds, which
made the radio unusable as a permanently attached modem - so that timeout was disabled
on request. The side effect was that the radio then stayed a modem forever and had to be
power cycled by hand after every test.

This ties the exit to the actual USB connection state instead: while the host is present
the radio stays a modem no matter how quiet it is, and as soon as the cable is pulled (or
the host stops enumerating it) the radio returns to normal operation by itself.
"""
W = "/home/viktor/ogd77rel/uv_src/OpenGD77_MDUV380_DM1701_20260130/MDUV380_firmware/application"
p = W + "/source/functions/hotspot.c"
s = open(p).read()

if "usbHostIsAttached" in s:
    print("already patched")
    raise SystemExit(0)

# a small helper next to the other statics
anchor = "static const uint32_t MMDVMHOST_TIMEOUT = MMDVMHOST_TIMEOUT_DISABLED;\n"
assert anchor in s, "timeout constant not found"

helper = anchor + """
// The USB device handle tells us whether a host is actually enumerating us. Losing that
// is what "the computer went away" really means; host silence alone is not.
extern USBD_HandleTypeDef hUsbDeviceFS;

static bool usbHostIsAttached(void)
{
	return (hUsbDeviceFS.dev_state == USBD_STATE_CONFIGURED);
}
"""
s = s.replace(anchor, helper, 1)

# make sure the USB device header is included
if '#include "usb_device.h"' not in s:
    inc_anchor = '#include "functions/ticks.h"\n'
    assert inc_anchor in s, "include anchor missing"
    s = s.replace(inc_anchor, inc_anchor + '#include "usb_device.h"\n', 1)

# both inactivity checks now also fire when the host has disconnected
old = """				if ((MMDVMHOST_TIMEOUT != 0) && (nonVolatileSettings.hotspotType == HOTSPOT_TYPE_MMDVM) &&
						((ticksGetMillis() - mmdvmHostLastActiveTime) > MMDVMHOST_TIMEOUT))
"""
new = """				if ((nonVolatileSettings.hotspotType == HOTSPOT_TYPE_MMDVM) &&
						((usbHostIsAttached() == false) ||
						 ((MMDVMHOST_TIMEOUT != 0) && ((ticksGetMillis() - mmdvmHostLastActiveTime) > MMDVMHOST_TIMEOUT))))
"""
count = s.count(old)
assert count == 2, "expected 2 inactivity checks, found %d" % count
s = s.replace(old, new)

open(p, "w").write(s)
print("hotspot.c: modem mode now ends when the USB host disconnects (%d checks)" % count)